Dublin Traffic Signal Priority

The Problem

In Dublin City, the main mode of Public Transport is by bus; the main operator is Dublin Bus, a State owned company with a fleet of over a 1,000 buses, most of which either terminate or pass through the city centre area. Optimising bus utilisation, reducing reliance on the car, reduce congestion and make roads safer, and optimising people movement around the city are strategic objectives of the authority. Public transport service improvements have been identified as:

Selected vehicle priority at traffic signals

Map based display for users to better understand bus performance

Status information on all buses, including ‘in congestion’ status

Colour coded information to assist operator intervention

Geospatial monitoring of occupancy journey times, count and queuing

Resolution to bus ‘bunching’

Like most authorities, money is limited so any solution that uses existing systems and data would be an attractive option.

The Solution

Nicander have delivered, for Dublin City Council (DCC) and Dublin Bus, an urban public transport priority system. It integrates existing public transport systems with the City’s urban traffic management and control system (SCATS) signalling to effect traffic signal priority for buses along the city’s Quality Bus Corridors.

The Dublin Bus AVL system provides a SIRI VM data feed which contains the position of each in-service bus in the fleet at a polling period of approximately 20 seconds. Data on whether the bus is in congestion or not and if the bus is loading passengers is also contained in this data feed. The application can make changes to the operation of any junction or junctions on the road network. For bus priority intervention, the methods of giving priority are:

Introduce a Bus Priority Timing Plan which involves providing timing adjustments for priority via a dedicated timing plan which can be automatically brought in for a specific time.

Introduce an Immediate Green signal on detection of a bus.

Implement a bias for the side road, automatically changes traffic signal behaviour to allow the main road to end its green signal if not busy

The client DPTIM application is a map based user interface displaying the latest status of the locations of the public transport vehicles by mapping the real-time SIRI VM data feed. The application provides a drawing interface which allows the user to map out virtual detectors to be used as hot-spots and detector points within the road network. These virtual detectors can be configured for specific route/journey patterns with the threshold values. Such thresholds would be allowed for queuing time, or the number of buses located within the geospatial area of that detector, or an acceptable journey time. Should the real-time values of these thresholds be breached, then the application calls a command on the SCATS/API.

DPTIM has achieved its main purpose of helping Dublin Bus deliver a reliable, efficient service to all of its customers. Operationally, the new DPTIM, with its faster updates, enables greater visibility of issues on the roads. Combined with the CCTV system DPTIM users are able to use this information to detect serious incidents on the network and react accordingly.